Hi, I know this looks like the same old same old, but I have tried all of the existing support queries or occurrences of this that I could find, but to no avail. So my FF 21 on Win7 suddenly stopped working. Whenever I tried running it, the process would appear in task manager, but no window would appear. No crash report, nothing. This also happened a month ago but the problem 'went away' which was a little disconcerting. So this time, I have tried uninstalling & re-installing multiple times, including removing all personal data (Backed up elsewhere) each time. Sometimes when I come to run a freshly installed instance, it will work. Whenever I tried importing my old profile, it would hang before displaying any window. So I figured I had a bad profile. I have since tried a fresh install followed by running the profile manager. If I click on 'create new' in profile manager, I can create a new profile but it goes to the 'Not responding' state before I can launch FireFox. This is without having any of my old profiles in place. Currently, I have another fresh install and am not even able to start it with the fresh default profile that was created. Even if I try to start in safe mode, I get the box asking if I want to start in safe mode and upon clicking 'Start in safe mode' the window just goes to 'Not responding'. I'm at a bit of a loss here as fresh installs now are even leaving me with a hanging FF and not even a clue as to what to look for. I understand that it may be an issue elsewhere on my system, but without even being able to launch FF, I am unable to diagnose further. Help! Tom...